Efficient light extraction and beam shaping from flexible, optically integrated organic light-emitting diodes

Efficient out-coupling light extraction and optical beam shaping have been combined to form an integrated, flexible illuminator that is based on organic light-emitting diodes (OLEDs). Spherical refractive microlenses were replicated by a cost-effective UV-casting technique onto a plastic foil to achieve the customized Gaussian distribution of the electroluminescence of an OLED pixel (50μm) matrix. The fabricated optical device, namely a ceiling light illuminator, shows an improvement of 70% in the out-coupled emission measured in the far field. The result corresponds to the theoretical prediction for isotropic emitting sources.

[1]  Michele Muccini,et al.  Ambipolar light-emitting organic field-effect transistor , 2004 .

[2]  C. H. Chen,et al.  Electroluminescence of doped organic thin films , 1989 .

[3]  S. Forrest,et al.  Nearly 100% internal phosphorescence efficiency in an organic light emitting device , 2001 .

[4]  T. Krauss,et al.  Spontaneous emission extraction and Purcell enhancement from thin-film 2-D photonic crystals , 1999 .

[5]  S R Forrest,et al.  High-external-quantum-efficiency organic light-emitting devices. , 1997, Optics letters.

[6]  Stephen R. Forrest,et al.  Improved light out-coupling in organic light emitting diodes employing ordered microlens arrays , 2002 .

[7]  Ifor D. W. Samuel,et al.  Increased Efficiency and Controlled Light Output from a Microstructured Light-Emitting Diode , 2001 .

[8]  Heinz von Seggern,et al.  Light-emitting field-effect transistor based on a tetracene thin film. , 2003, Physical review letters.

[9]  C. Tang,et al.  Organic Electroluminescent Diodes , 1987 .

[10]  J. Joannopoulos,et al.  High Extraction Efficiency of Spontaneous Emission from Slabs of Photonic Crystals , 1997 .

[11]  Donal D. C. Bradley,et al.  Angular Dependence of the Emission from a Conjugated Polymer Light‐Emitting Diode: Implications for efficiency calculations , 1994 .

[12]  Piero Cosseddu,et al.  Tetracene light-emitting transistors on flexible plastic substrates , 2005 .

[13]  Stephen R. Forrest,et al.  Weak microcavity effects in organic light-emitting devices , 1998 .

[14]  A. Scherer,et al.  30% external quantum efficiency from surface textured, thin‐film light‐emitting diodes , 1993 .

[15]  M. T. Gale,et al.  Optical coupling of flexible microstructured organic light sources for automotive applications , 2003 .

[16]  R. N. Marks,et al.  Light-emitting diodes based on conjugated polymers , 1990, Nature.

[17]  S. Forrest,et al.  Highly efficient phosphorescent emission from organic electroluminescent devices , 1998, Nature.

[18]  Eli Yablonovitch,et al.  Ultrahigh spontaneous emission quantum efficiency, 99.7% internally and 72% externally, from AlGaAs/GaAs/AlGaAs double heterostructures , 1993 .

[19]  Michele Muccini,et al.  Morphology and Field‐Effect‐Transistor Mobility in Tetracene Thin Films , 2005 .

[20]  W. Riess,et al.  Tuning Optoelectronic Properties of Ambipolar Organic Light‐ Emitting Transistors Using a Bulk‐Heterojunction Approach , 2006 .

[21]  Chihaya Adachi,et al.  Singlet-singlet and singlet-heat annihilations in fluorescence-based organic light-emitting diodes under steady-state high current density , 2005 .

[22]  N. Tessler.  Transport and optical modeling of organic light-emitting diodes , 2000 .